Fuse



y 6, 1952 E. w. BRANDT 2,595,757

FL'ISE Filed July 11, 1947 4 Sheet s-Sheet 1 (Ittornegs E. w. BRANDT2,595,757

FUSE

May 1952 Filed July 11, 1947 4 Sheets-Sheet 2 3nnentor attorneys May 6,1952 Filed July 11, 1947 E. w. BRANDT FUSE 4 Sheets-Sheei 3 ZmnentorGttomegs May 6, 1952 E. w. BRANDT 2,595,757

FUSE Filed July 11, 1947 4 Sheets-Sheet 4 m as.

giZfi 7 inventor (Ittomegs Patented May 6, 1952 FUSE Edgar WilliamBrandt, Geneva, Switzerland, assignor to Anstalt fur die Entwicklung vonErfindungen und Gewerblichen Anwendungen Energa, Vaduz, Liechtenstein, acorporation of Liechtenstein Application July 1 1, 1947, Serial-No.760,425 In Switzerland November 2, 1946 This invention relates to iuzeshaving a mechanical delay device.

Numerous types of fuze are already known which are designed to bemounted in the ogival head, inside or at the base of explosiveprojectiles, and which comprise devices intended to ensure securityagainst shock during storage or handling, security'in the bore onfiring, to give delayed arming in order to avoid premature bursting ofthe projectile if the latter should, after discharge, encounter anunexpected obstacle, such as camouflage, branches, or the like, in thevicinity of the firer, and, moreover, to ensure on impact eitherinstantaneous or delayed bursting.

Such fuzes generally comprise a fairly complicated mechanical device,the functioning of which is controlled either by a clockwork move? mentor directly by the forces acting on the projectile on the firing of theshot.

The present invention relates to fuzescomplying with the above-mentionedconditions and with all requirements, while being of simpleconstruction, capable of being made of very small dimensions, comprisinga minimum of parts, being adapted to resist the stresses developed onthe discharge of the shot, and, if so required, to resist the impactshock.

The fuzes of the present invention are of the type which are providedwith a mechanical arming delay device, or mechanical safety orfiringdevice, comprising essentially two co-actingparts, one of whichcomprises at least one groove and the otherat least one slide adapted torun in 3 Claims. (01. 10278) inertia block in imposing it a rotaryoscillating movement.

The opposing member can be an elastic opposing member such as, forinstance, a spring.

With such a device, security against shock during storage and handlingof the projectiles, as well as security in the bore of the gun on,firing, and muzzle'safety are absolute, since no accidental force canact on the inertia block simultaneously in the axial direction and inthe tangential direction, nor for a sufiicientlv long space of time tocause the slide to follow, first in one direction and then in the other,the zig-zag V- shaped path presented by the groove, which can only takeplace after the shot has been fired and within the period of timecorresponding to the desired delay.

The length of the groove, the number and extent of the zig-zags, thediameter and the weight said groove, and are characterized by the factthat one of said co-acting parts is an inertia block maintained in asafety position by the action of at least one opposing member, and thatthe groove comprises two converging branches disposed substantially inthe shape of a V and imposes on the slide forming the bolt, at least inone of its branches, a zig-zag path, so that, under the action of asustained thrust greater than the action of the opposing member, saidinertia block passes from the safety position to an intermediateposition, the slide being caused to fork'from one of the branches ofthegroove into the other; the inertia block can from that moment reach thearmed position when the thrust effect greater than the action of theopposing member ceases, its displacement havingrtaken'place first in onedirection, in accordance with one of the branches of the groove, then inthe opposite direction, under theopposing force, in accordance withtheother branch of the groove; saidjzig-Za P having thus slowed downthedisplacement of the of the inertia block are so many factors whichcan be varied at will in order to increase or decrease the desiredefiect, which is to delay the moment when the arming of the fuze or theignition takes place.

The fuze can be designed with consideration to the characteristics ofthe equipment serving to discharge the projectile, the value of thecharges employed, the pressures and the accelerations given to thefiring of the shot, while assuring either time operation or impactoperation, or again, while providing the desired bursting effects suchas instantaneous or delayed burst.

According to onefeature of the invention, the aforesaid groove comprisestwo unequal branches, one at least of which is blind, that is to sayends in a cul-de-sac. The longer of said branches is preferably open atthe end. In the position of rest, or the safety position, theslideforming the bolt preferably abuts against the end of the blindbranch, the inertia block being immobilised in that position by thethrust of the opposing memher, for example a spring, which tends to keepthe slide abutting thereagainst.

Under the action of a sustained thrust greater than the action of theopposing member, such as a positive or negative acceleration, theinertia block is displaced, following the oscillating movement imposedon it by the zig-zag shape of the groove, and the slide proceeds tooccupy at the point of the V the intermediate position in which it isengaged in the long branch of the groove. When the thrust oracceleration action ceases, the opposing member reacts, pushing back theinertia block in the opposite direction, while the slide runs along saidbranch of the groove, escapat the bottom of the blind groove, and theinertia block does not move.

If the accidental shock takes place in the opposite direction, only aslight displacement of the inertia block results; as the latter'issubjected, during this displacement, to the zig-zag movements imposed onit by the groove, it will be stopped by the fact that an axial shockcannot give rise to the necessary rotary lateral movement, and theopposing member will bring back the inertia block to its original safetyposition before the slide reaches its intermediate position at the pointof the V formed by the groove.

This device, used for example to bring about delayed arming andmechanical functioning in an og'ival fuze, is also suitable, by simpleinversion or change of direction, for carrying out similar functions ina base fuze, or again in a firing device located inside the projectile.

Thus, in one particular embodiment of the in vention, the groovecomprises a long branch and a, blind cavity in which the slide isadapted to engage in such manner as to lock the inertia block, undr theaction of the opposing member, when it comes into the armed position.

In this case, the slide first runs along the long branch of the grooveunder the action of a thrust, such as the propulsive force of theprojectile, and then, when said thrust ceases, it is pushed back by theaction of the opposing member into the blind cavity, which replaces theshort branch of the groove, and thus immobilises the inertia block,which has come into the armed position.

In accordance with a further feature of the invention, the fork of thetwo branches of the groove is disposed in such manner that one of them,preferably the blind branch, joins the other laterally.

In this manner the slide, when it has run along one of the branches ofthe groove, engages in the other before or on abutting against the pointof the V, and cannot re-enter the branch that it has just left; forkingfrom one branch into the other is thus ensured in certain manner.

It may be desired that the displacement of the inertia block under theaction of the opposing member should be rapid and undelayed when theslide leaves its intermediate position.

In this case, the long branch of the groove will be rectilinear andpreferably disposed in the axial direction, only the blind branch beingzigzag in shape.

In order to reduce the effects of inertia and to avoid all risk ofcaulking, deformation, and parasitic friction liable to affect theefficiency of operation of the device when it is desired that the lattershould be able to resist very violent forces or shocks, for example onthe firing of I the shot, provision hasbeen made, according to still afurther feature of theinvention, to increase the number of the zig-zagsand to decrease their pitch, to such an extent as to give to at leastone branch of the groove a generally undulatory outline.

Moreover, in order to ensure, simply and perfectly, the passage of theslide from one branch of the groove into the other, and toavoid lateraltension of the opposingmember, particularly if a spring is involved, thebranches of the groove are disposed in such a manner that the safetyposition and the intermediate position of the slide are on the samelongitudinal axis.

It is naturally understood that the use of a lateral tension of thespring to ensure the functioning of the device is in no way excluded.

In one embodiment, the slide is a finger integral with one of the twoco-acting pieces. I In another embodiment, a ball partially imprisonedin a groove provided in one of the two co-acting pieces attends to thesame function.

Convenient solutions can be found for numerous problems by the practicalapplication of devices complying with the features of the invention,among them, in particular, the following different cases:

A device comprising a cap-carrying inertia block provided with a groovein accordance with the invention;

A device comprising a cap-carrying inertia block provided with a slidein accordance with the invention;

A device comprising a striker-carrying inertia block provided with agroove in accordance with the invention;

A device comprising a striker-carrying inertia block provided with aslide in accordance with the invention;

A device comprising a cap carrier-detonator adapted to pass from aninactive safety position relative to the explosive charge of theprojectile to an active position in which the transmission of theexplosion can take place normally on impact.

In one example of a fuze corresponding to the features of the invention,two concentric coacting inertia blocks are provided, one of which isimmobilised in the safety position in the body of the fuze, through themedium of a yielding member, such as a ball, the liberation of which isdependent on the functioning of the other inertia block, which issubject to the action of the opposing member.

Retarded arming on firing of the shot is thus simply obtained in aninstantaneous percussion fuze for projectiles propelled by a gun oracquiring their speed through a self-propelling charge and provided witha percussion head adapted to be driven back on impact.

The external inertia block. can be disposed in such manner as to give,in the safety position, supplementary protection to the cap set back inthe internal inertia block.

The invention also enables a very simple fuze to be designed forprojectiles propelled by a gun or by self-propulsion, the arming ofwhich takes place only on impact, the functioning of the fuze takingplace through delayed percussion, only after braking and stopping of theprojectile in the ground or any other objective, the opposing memberbeing disposed in such manner that it reacts on the inertia block onlyon impact, the delay being produced at that moment.

Finally, the device of the invention can also be utilised to liberate,with delay, an obturator designed to prevent transmission of fireprematurely.

In this case, the inertia block can take the form of an obturating bellwhich, in the safety position, covers the piece with which it co-actsthrough the medium of the slide and groove of the invention, said bellpreventing the transmission of fire until it is ejected by the action ofthe opposing member. Y

Other advantages and features of the invenreadily understood, referenceis made to the ac-' 'companying drawings which illustrate diagrammatically' and by way of example, various embodiments thereof, andinwhich:

Figs. l'to '7 inclusive represent in axial section a fuze: in accordancewith the invention and, in front view, its inertia block provided withgrooves, in the various stages of operation;

Figs. 8, 9 and 10' show a fuze comprising a mobile detonator, in thesafety position and in the armed position, as well as its inertia block;

Figs. 11 and 12 represent respectively a fuze intended to be placedinside a projectile, and its inertia block; 2

Figs. 13 and 14 illustrate respectively an inertia fuze with delayedarming, and its inertia block;

Figs. 15 to 22 inclusive represent respectively various modifications ofdevices according to the invention, comprising an inertia block forminga bell-designed to prevent premature firing;

Fig. 22a shows an application of the device represented in Figs. 15 and22.

Figs 23 to 27 inclusive represent respectively in various stages ofoperation,- a fuze designed to function with delayed percussion,together with its inertia block.

In order to facilitate understanding, parts serving the same purposeineach of the various figures have been designated by the same referencenumerals.

' The fu'zeillustrated in Figs. 1 to '7 is composed of a fuze body Iprovided in front with a percussion head 2, with a striker 3 and, at therear, with a detonator 4'. An inertia block 5 provided with a cap 6 andsubject to the action of a compression spring I, which acts as opposingmember by hearing against a rear rest 8 on the fuze body, is adapted tomove axially in a cylindrical cavity 9 provided in the member co-actingwith said inertia block 5. This co-acting member is generally the body Iitself; in the embodiment illustrated in Figs. 1, to '7, this member isa second inertia block II) concentric with the inertia block 5' andresting, in the safety position, on an annular projection II on the bodyI; this second inertia block I is disposed to be movable axially insidea cylindrical cavity I2 formed by the fuze body I.

Union between the two inertia blocks and Ill which are co-acting andconcentric is achieved, according to the invention, by means of a slideI3 integral with the external inertia block I0 and adapted to run alonga groove I4 hollowed out in the periphery of the internal inertiablock-5.-

The groove I4 (Fig. 2)' comprises two branches of unequal lengths I iaand I4b, disposed in the shape of a V and providing a zig-zag path forthe slide I3. The long branch Ma is open at its end I5, while the shortbranch I4b is blind, that is to say ends in a cul-de-sac at I6. Theblind branch Mb runs laterally into the long branch I 4a,'near the endI! of the latter, in such manner that the slide I3, when it is engagedin the long branch, can no longer go back into the blind branch.

A ball i=8 lodged in aperture I9 in the external inertia block I3(Fig. 1) projects from its aperture, in the safety position, and isengaged in a circular recess 29 provided inside the cylindrical cavityI2, thus immobilising said inertia block IB with the slide I3 when inthe safety position.

6 The spring I for its part holds the grooved inertia block 5 againstthe bottom of the blind groove Itb in the slide I3 acting as bolt.

The outer inertia block Ill, which serves as seating for the innercap-carrying inertia block 5, is adapted to act as a stop for the head2' carrying the striker in the event of said head being accidentallydriven into the interior of the fuse body I; to this end, said inertiablock III is sumciently long so that the striker point 3 can in no casecome into contact with the cap I5 as long as the latter is in the safetyposition (Fig. l), withdrawn in the cylindrical cavity 9.

The striker-carrying head 2 is immobilised by a pin 2i shearable onimpact, or by any other means, such as, for example, a circular stop(not shown in the drawings) resting on a thin washer, which is likewisshearable on impact.

Complete tightness of the fuse is obtained by means of an elastic mass22, consisting of cork, for example, and acting as a stopper at theextremity of the cylindrical cavity I2.

A spring 23, completely expanded, is placed in the housing constitutedby the front part of the cylindrical cavity I2, between the internalface 24 of the striker-carrying head 2 and a shoulder 25 on the outerinertia block I9. This Very weak spring 23 serves to keep th unitcomprising the two inertia blocks 5 and I0, and therefore the cap 6, ata distance from the striker point 3 when the fuze is armed, and enablesthe fuze to be given extreme sensitiveness to impact.

In the event of dropping, or if there should be a blow on the fuze head,with sufficient force to shear the pin 2|, while the inertia blocks 5and Illare in the safety position (Fig. 1), the strikercarrying head canwithout danger strike with its face 2s against the extremity 26 of theinertia block I8, because the striker point 3 is too short to reach thecap S. The cap-carrying inertia block 5- itself, being immobilised bythe slide I3 at th bottom of the path in the blind groove I4b (Fig. 2),cannot move forward; percussion is therefore impossible.

In the case of a blow in the opposite direction, the slide I3 acts as abolt in the zig-zag groove 54 under the thrust of the spring I, and thusthese three members resist any substantial displacement of thecap-carrying inertia block 5, which immediately returns to bear againstthe slide I3 at the bottom of th blind groove, at I6.

The mode of operation of the fuze illustrated in Figs. 1 to 7 is asfollows:

On the firing of the shot, the inertia block 5, through inertia underthe propulsive action, compresses the spring I and moves backwards tobear against a circular flange 21 on the fuse body I, taking up theposition shown in Fig. 3, while the slide I3, running along the blindbranch Nb of the groove I5, takes up its position at the point ll of theV (Fig. l), where it is engaged in the long branch I 4a, in theintermediate or pre-arming position. From that moment it can no longerre-enter the side branch Mb that it has just left.

When the positive acceleration ceases, the spring I pushes thecap-carrying inertia block 5 forward again, the slide I3 then making useof the long branch Ida of the groove, the Zig-zag shape of which obligessaid inertia block to perform on its axis an oscillating movement whichsloWs down its axial displacement, while the outer inertia block Illstill remains immobilised in the fuse body I by the ball I a-imprisonedin the aperture I9 and in the recess 20.

Before reaching the front extremity of the cylindrical cavity 9, theinertia block 5 releases the ball [-8, which escapes to the interior(Fig. 5), and then the slide l3, which emerges through the open end [5of the groove 14a. The outer inertia block 10, being released, isin turncarried along axially by the inner inertia block 5 as soon as the latterstrikes against a rim 28 on the inertia block H), causing the cap 5 toproject forwards through the latter.

When the parts are.in this position, the fuze is armed, the striker 3and the cap 6 being held apart from one another only by the weakresistance of the spring 23, while the spring i is completely extended.

From that moment percussion is ensured on impact, either by the drivingback of the strikercarrying head 2 after shearing of the pin 2! (Fig.6), or by inertia, the cap-carrying inertia block 5 and the outerinertia block l both moving forwards towards th point of the striker inthe event of striker-carrying head 2 not having been'driven back by theobjective (Fig. '7).

Figs. 8 to 10 illustrate a shell fuze capable of ensuring at the sametime complete safety during storage and on firing, including preventionof any rebound, with displacement of the detonator cap which passes froman inactive safety position relative to the explosive charge of theprojectile to an active position, in which the explosive transmissioncan normally be produced on impact.

A fuze body I, bored from end to end with a single diameter, carriesslides l3 serving as stop and control fingers and disposed in such amanner asv to be able to slide in the corresponding grooves M provided,in accordance with the invention, in an inertia block 5 placed at anydesired distance inside the body I.

Each groove M (Fig. 9) comprises two branches Ma and Mb disposed in theshape of a V, which provide a zig-zag path for the appertaining slide.

A spring 1 applies at one end a pressure against the inertia block 5,which keeps it bearing against the slides 13 at the bottom of the blindgrooves Mb, and, at the other, keeps'the. detonator 4, mounted on asecond inertia block [0, bearing against the rear end 29 of the fuzebody I.

A spring 38, decidedly weaker than the spring I, remains compressed inthe waiting position between the lower surface 3! of the inertia blockIn and the bottom 29 of the fuze body.

A striker-carrying stopper 2, placed in the head of the fuze body I,attends to the sealing of the latter; this stopper is provided with anextended striker 3, which passes right through the grooved inertia block5 and enters the interior bore 9 of the cap-carrying inertia block Iii,at the base of which is located the cap 6.

' In the case of an accidental blow on the fuze, the grooved inertiablock 5 will react as described above and ensure the absolute safety ofthe device.

On the firing of the shot, said inertia block 5, under the influence ofthe propulsive effect and through inertia, causes the spring 1 to yield,travels backwards in a reciprocating rotary movement imposed on it bythe branches Mb of the grooves, and the slides l3 move to the point ofthe V, at N (Fig. 9)

After firing, at the end of the propulsive thrust, the spring I returnsthe inertia block 5 forwards, the slides 13 then each utilisingrespectively the zig-zag pathsof the grooves 14a. By reason of thebackward and forward travel, displacement of the inertia block towardsthe front is slowed down until the slides l3, reaching the end iii ofthe grooves Ma, escape from the latter. At that moment, no longer underthe influence of the spring 1, which is extended, but under that of thespring 30, the parts take up the armed position illustrated in Fig. 10.Percussion on impact is from that moment ensured.

The device forming the subject of the invention can also be utilised insuch manner as to operate a pyrotechnical or mechanical time fuze, asillustrated in Fig. 11.

The fuze body I, bored throughout it length, is provided with adetonator-carrying head 2 carrying a cap 5 and a detonator 4. A slidel3, integral with the body I, is engaged in thesafety position in theblind branch Mb of a V-shaped zig-zag groove M disposed on astriker-carrying inertia block 5 which a spring 1, bearing on the base29 of said body, holds against the slide i3 at the bottom of the blindgroove Mb.

In the case of accidental shock, the strikercarrying inertia block 5 isheld in the safety position, as hereinabove described, by the combinedaction of the'slide I3, the groove M, and the spring 1.

On the firing of the shot, the striker-carrying inertia block 5, underthe influence of the propulsive effect and following the movementsimposed on it by the zig-zag groove Mb, compresses the spring "I untilthe slide 13 reaches the end of the blind groove, where it forks intothe long groove Ma. As soon as the propulsive effect ceases, the springI returns the inertia block forwards; it then follows the movementsimposed on it by the long branch Ma of the groove, and then, when theslide l3 reaches the outlet l5 of the latter, it is released and isthrown by the spring 1 towards the cap 6, in which its point penetratesand gives rise to the firing.

Fig. 12 shows that the blind branch Mb of the groove may, like the longbranch Ma, have several successive zig-zags, the effect of which is toincrease the delay and not to permit the slide [3 to assume thepre-arming position I! except under a longer thrust effect.

Figs. 13 and 14 relate to a device combined in such a manner as toobtain an inertia fuze with delayed arming, for projectiles preferablypropelled by self-propulsion.

The fuze comprises a body I in which are housed a grooved inertia block5 provided with a striker 3, a cap-carrying inertia block l0 providedwith a cap 6 and a detonators, and a spring 7 bearing at one end on thestriker-carrying inertia block and, at the other end, on the capcarryinginertia block. In the safety position, the sring -1 tends to keep thetwo inertia blocks apart from one another. The total path available tothe cap-carrying inertia block [0 as far as a stop 32 provided on thefuze body does not enable the cap to touch the striker point.

Since, moreover, the striker is immobilised, as hereinbefore described,.by the combined action of slides I3 on grooves M and of the spring 1 onthe grooved inertia block 5, security against shocks, either on the'noseof the fuze or in the opposite direction, is assured.

In this particular case, the blind branch Mb of the groove 14 is reducedto a blind cavity I6 adapted to receive the slide l3 at the end of thepath, said slide being located at the entrance l5 of the long branch Ma(Fig. 14) as long as it is in the safety position.

On the firing of the shot, under the influence of the propulsive effectthe striker-carrying the rear until the slide 13, has reached theextremity ll of said groove.

As soon as the propulsive effect ceases, the spring 1 returns theinertia block 5 in the opposite direction; the slide 13, taking upposition in.

the cavity 16 which forms a stop, thus keeps the striker 3 held in suchmanner that, on impact, the point 3 will penetrate the cap 6 when thecap-carrying inertia block Iii meets it.

In one particular embodiment of the invention, the device of theinvention may also be utilized to release, with delay, an obturatordesigned to prevent premature transmission of firing (Fig. .15).

Inside a suitable jacket 1, an inertia block 5 forms an obturation belland carries a slide [3 in the form of a stop and control finger. Thebell inertia block 5 fits over and caps a projection forming a support33, which constitutes the coacting member and carries the zig-zag groove[4 (Fig. 16),,and has the central aperture 33a through which fire canpass to the detonator.

An ejection spring 1 in this aperture holds the bell inertia block 5against the slide 13 at the bottom of the blind groove Mb of the support33.

In this safety position, the bell prevents the transmission of firing orof the explosive wave from the cap of a fuze located in the front ornose end of the projectile.

On the firing of the shot, the bell inertia block 5, under the influenceof the propulsive effect and through inertia, follows the movementsimposed on it by the blind groove Mb, compressing the spring 1 until theend of the path of the slide I 3 in said groove, said slide then takingup position at IT.

As soon as the propulsive effect ceases, the spring I returns theobturation bell 5 to the front; said bell then follows the movementsimposed on it by the zig-zags of the long branch Ma of the groove inwhich the slide I 3 runs, and then, when the latter reaches the outletl5 of said groove, the bell is ejected by the spring 7, thus freeing thefire passage orifice. Transmission of firing may take place from thatmoment on.

The specific structure shown in Fig. 15 has the body I formed with acylindrical inner wall spaced from the projection or support 33 toprovide an annular cavity in which is closely received the cylindricalskirt 5b of the obturator bell. The externally conical closed forwardend 5a of the bell is thicker than the lateral skirt Wall 5b. Theillustrated arrangement has the technical advantage of increasing thesafety factor of the mechanical delay device. Thus, if premature firefrom a nose primer of a fuze 37 (Fig. 22a)'is projected against the head5a, While the obturator is in safety position, the fire is compelled tofollow a tortuous path between the wall 1 and the skirt of the obturatorbell 5, and then between this skirt and the coaxial projection 33, andfinally through the central aperture or passage in the projection 33.The illustrated shaping and proportioning of the 'j'closed forward endprovides greater heat absorp- 1 5. .11 angg te ame t "p fi ation curinil rie jfiir ns. peri d o the jr imer c n J v Fig. 17 illustrates a'modification-of the device illustrated in Fig. 15,. in whichmodification the slide I3 is integral with the jacket I, while thegroove I4 is carried by the bell inertia block 5 and is disposed in theopposite direction (Fig. 18). The mode of operation is the same as inthe case of Fig. 15.

the

In the modification illustrated in Fig. 19, the general disposition isthe same as in the case of Fig. 15, but it comprises two groovesdisposed in such manner that the ejection of the bell inertia block 5 isinstantaneous when theslide i 3 is caused to leave its intermediateposition. This result is obtained by giving the long branch of Na of thegroove a rectilinear shape,

while only the blind branch Mb has zig-zags.

(Fig. 20). The spring 7 being very weak in order to give the devicegreat sensitiveness, the branch Mb of the groove hasbeen made longerthan hitherto in order to force the slide to travel over a longerzig-zag path before reaching the intermediate position II.

In addition, by way of example, the slide is designed in the form of aball is imprisoned in a recess .34 in the bell inertia block 5, whichgives it greater flexibility in operation.

In order to enable the device to resist even very violent shocks, eitherduring handling or on the firing of the shot, and to avoid all risk ofcaulking, deformation, or parasitic friction liable to impair goodoperation, provision has been made, in the arrangement illustratedinFig. 2l,for a greater number of backward and forward movements in thegroove 14, while reducing the length of each such movement. The branchesMa and Mb of the groove time assume a generally undulatory shape.

The grooves may also be disposedin the manner illustrated in Fig. 22, sothat the safety position l6 of the slide l3 and its intermediate orpre-arming position I! are in the same longitudinal axis X--X. Whileensuring in perfect fashion the passage of the slide l3 from the grooveMb into the groove Ma, this enables all lateral tension of the returnspring 7 to be avoided in the event of that occurring in consequence ofthe oblique position of the groove.

Fig. 22a shows how the obturator device described in connection withFig. 15 may be employed in'a projectile 4| having a cavity 42 betweenthe front end and the obturator 5. The primer cap in an impact fuze 3!at the nose of the projectile is to be fired on impact, transmitting.its fire or explosive wave rearward through this cavity along the axisof the projectile: but so long as the obturator bell 5 is in safetyposition, the detonator 38 is not energized. Thus, the device is safeagainst explosion of the charge 39, 40 prior to the normal propulsion ofthe projectile. During the early part of thetrajectory of theprojectile, the obturator hell 5 moves rearward from its safetyposition, with its slide I3 passing from the 'full line position to thedotted line position of in Fig. 2%., thereby uncovering the aperturethrough the 'projectioufit (Fig; '15) and permitting the fire fromtheprime r cap of fuse .37

11 then to have passage through the aperture to the detonator 38 forenergizing the same, wherewith the explosive charge 39, 40 is detonated.

The device forming the subject of the invention also renders it possibleto provide, for projectiles discharged by guns or by self-propulsion, avery simple fuze the arming of which takes place on impact, operation bydelayed percussion taking place only after braking or stoppage of theprojectile in the ground or any other objective.

Figs. 23 to 2'7 relate to such a device. A capcarrying fuze body I ofgreat strength carries the slide or slides l3, the groove or grooves l4being placed on a striker-carrying inertia block 5; a spring 1 holdssaid inertia block, in the safety position, against the slide l3 at thebottom of the blind groove Mb (Figs. 23 and 24). A supplementary stop,for example consisting of balls 35, may if desired be provided (Fig.2'7) if firing is to take place with very great accelerations ondischarge of the shot.

Safety in the position of rest is ensured by the cooperation of theslide I3, the groove [41), and the spring I, in the same manner ashereinbefore described.

n the firing of the shot, the position of the parts remains unchanged.On impact, the projectile loses its speed and, after penetration to agreater or lesser degree, depending on the resistance of the target, iscompletely stopped. In consequence of this braking effect, thestrikercarrying inertia block 5, owing to its residual kinetic energy,is carried forward, compressing the spring 1 (Fig. 25).

In the embodiment illustrated in Fig. 27, the balls 35, released whenthe inertia block moves forward, leave their annular housing 36 and takeup position behind the inertia block.

As soon as the projectile has stopped, the spring I returns the inertiablock 5 to the rear, the zig-zag groove Ma first imposing on it a slowmovement after which, when the slide I3 leaves said groove, the spring 1throws the strikercarrying inertia block 5 against the cap 6, whichfires.

What I claim is:

1. A mechanical safety delay device for a projectile fuze having a bodywith an aperture through which fire is to be transmitted as an incidentof detonation, comprising two main co-acting parts, one of which partsis an ejectable obturator and the other part is a body projection havingsaid aperture extending therethrough, said obturator part having theshape of a bell and being located when in safety position around saidprojection and covering the aperture and thereby preventing thetransmission of fire, one of said main co-acting parts having at leastone groove formed by two converging branches, the other of saidco-acting parts having a sliding member adapted to run in said groove,one branch of said groove having a blind end for receiving the slidingmember when in safety position and preventing forward movement of thesaid obturator part, said one branch having a zig-zag shape forco-acting with the sliding member during positive acceleration of theprojectile and thereby effecting a slowing down of theinertial relativerearward movement of the obturator part by rotary oscillating movementsimparted thereto, the converging point of saidg-branches being axiallyaligned with the ,said. .oth,er branchthereof so that a forward movementof the obturator part after the sliding member has come to theconverging point will cause the sliding member to enter the said otherbranch, said other branch having an open end remote from said convergingpoint whereby the sliding member is released by the groove duringforward movement of the obturator part while the member is moving alongsaid other branch, and therewith the obturator is ejected from itscovering position, and an op posing member effective to maintain saidobturator part normally in a safety position prior to the positiveacceleration of the projectile.

2. A mechanical safety delay device for a projectile fuze having a bodywith an aperture through which fire is to be transmitted as an incidentof detonation, comprising two main co acting parts, one of which partsis an ejectable obturator and the other part is a body projection havingsaid aperture extended therethrough, said obturator part having theshape of a bell with the forward end thereof being a head of externalconical shape and having greater thickness than the lateral wall portionof said bell, the bell being located when in safety position around saidprojection and covering the aperture and thereby preventing thetransmission of fire, one of said main co-acting parts having at leastone groove formed by two converging branches, the other of saidco-acting parts having a sliding member adapted to run in said groove,one branch of said groove having a blind end for receiving the slidingmember when in safety position and preventing forward movement of thesaid obturator part, said one branch having a zig-zag shape forco-acting with the sliding member during positive acceleration of theprojectile and thereby effecting a slowing down of the inertial relativerearward movement of the obturator part by rotary oscillating movementsimparted thereto, the converging point of said branches being axiallyaligned with the said other branch thereof so that a forward movement ofthe obturator part after the sliding member has come to the convergingpoint will cause the sliding member to enter the said other branch, saidother branch having an open end remote from said converging pointwhereby the sliding member is released by the groove during forwardmovement of the obturator part while the sliding member is moving alongsaid other branch, and therewith the obturator is ejected from itscovering position, and an opposing member efi'ective to maintain saidobturator part normally in a safety position prior to the positiveacceleration of the projectile.

3. A mechanical safety delay device for a projectile fuze having a bodywith an-aperture through which fire is to be transmitted as an incidentof detonation, comprising two main co-acting parts, one of which partsis an ejectable obturator and the other part comprises a body projectionhaving said aperture extended therethrough and a peripheral cylindricalwall spaced from and concentric with said projection, said obturatorpart having the shape of a bell with a cylindrical skirt closely fittingand movable in the space between said projection and said wall, saidbell when in safety position covering the aperture in said projectionand thereby preventing the transmission of fire through said aperture,one of the said main co-acting parts having at least one groove formedby two converging branches, the other of said co-acting parts having asliding member adapted to run in "said groove, one branch of said groovehaving a blind end for receiv'ingthe sliding member when down of theinertial relative rearward movement of the obturator part by rotaryoscillating movements imparted thereto, the converging point of saidbranches being axially aligned with th said other branch thereof so thata forward movement of the obturator part after the sliding member hascome to the converging point will cause the sliding member to enter thesaid other branch, said other branch having an open end remote from saidconverging point whereby the sliding member is released by the grooveduring forward movement of the obturator part while the member is'movingalong said other branch. and therewith the obturator is ejected from itscovering position, and an opposing member effective to maintain saidobturator part normally in a safety position prior to the positiveacceleration of the projectile.

EDGAR WILLIAM BRANDT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,053,857 Nordenfelt Feb. 18,1913 1,792,631 Deevy Feb. 1'7, 1931 FOREIGN PATENTS Number Country Date18,185 Great Britain of 1905 359,102 Germany Sept. 19, 1922 489,020Great Britain App. data 1936 695,190 France Sept. 29, 1930

